SVGs are images, it stands for Scalable Vector Graphic. You can rightclick on the rendered chart and save it as an image in your browser just as you would do with any normal image.
If you are looking to capture the chart at various points throughout the day you might want to look at the toHtml() function in the render class and filter it from there. I would need to have a look at the render classes at home in order to advise better if it is the programmatic route you are taking.